Neuronal nitric oxide synthase (nNOS) catalyzes the oxidation of L-arginine to L-citrulline in the central nervous system, generating nitric oxide (NO), a critical neurotransmitter. Significant research has implicated the overexpression of nNOS—and overproduction of NO—in various neurological diseases, including Parkinson's, Alzheimer's, and Huntington's diseases, as well as neuronal damage due to stroke, cerebral palsy and migraine headaches. Inhibiting endothelial nitric oxide synthase (eNOS) and inducible nitric oxide synthase (iNOS) is, however, undesirable, because these isozymes are responsible for maintaining crucial body function. Thus, selective inhibition of nNOS over its closely related isoforms, eNOS and iNOS, has provided a promising strategy in the development of therapeutics for the treatment of neurodegenerative diseases. However, while certain compounds have exhibited good potency and high selectivity, they often suffer from poor bioavailability. As a result, there remains an on-going search in the art for effective bioavailable NOS inhibitors to realize the therapeutic potential of such compounds.